Further improvemens to texture resolution. (#16)

* Further improvemens to texture resolution.

- Move towards std::string over char * and FbxString where convenient,
- Make a clear distinction between textures whose image files have been
  located and those who haven't; warn early in the latter case.
- Extend RawTexture so we always know logical name in FBX, original file
  name in FBX, and inferred location in local filesystem.
- In non-binary mode, simply output the inferred local file basename as
  the URI; this will be the correct relative path as long as the texture
  files are located next to the .gltf and .bin files.

Primary remaining urge for a follow-up PR:

- We should be copying texture image files into the .gltf output folder,
  but before that we should switch to an off-the-shelf cross-platform
  file manipulation library like https://github.com/cginternals/cppfs.
  When we make that transition, all this texture resolution code will
  undergo another refactoring.

src/Fbx2Raw.cpp

@@ -106,7 +106,7 @@ class FbxMaterialAccess
 
 private:
     const FbxSurfaceMaterial *fbxMaterial;
-    const std::map<const FbxTexture *, FbxString> &textureNames;
+    const std::map<const FbxTexture *, FbxString> &textureLocations;
 
 public:
     const FbxString name;
@@ -119,7 +119,7 @@ public:
         fbxMaterial(fbxMaterial),
         name(fbxMaterial->GetName()),
         shadingModel(fbxMaterial->ShadingModel),
-        textureNames(textureNames),
+        textureLocations(textureNames),
         props(extractTextures())
     {}
 
@@ -180,7 +180,7 @@ public:
 
         FbxDouble val(0);
         FbxFileTexture *tex = prop.GetSrcObject<FbxFileTexture>();
-        if (tex != nullptr && textureNames.find(tex) == textureNames.end()) {
+        if (tex != nullptr && textureLocations.find(tex) == textureLocations.end()) {
             tex = nullptr;
         }
         if (tex == nullptr && prop.IsValid()) {
@@ -195,7 +195,7 @@ public:
 
         FbxDouble3 val(1, 1, 1);
         FbxFileTexture *tex = prop.GetSrcObject<FbxFileTexture>();
-        if (tex != nullptr && textureNames.find(tex) == textureNames.end()) {
+        if (tex != nullptr && textureLocations.find(tex) == textureLocations.end()) {
             tex = nullptr;
         }
         if (tex == nullptr && prop.IsValid()) {
@@ -213,14 +213,14 @@ public:
         FbxDouble  factorVal(1);
 
         FbxFileTexture *colTex = colProp.GetSrcObject<FbxFileTexture>();
-        if (colTex != nullptr && textureNames.find(colTex) == textureNames.end()) {
+        if (colTex != nullptr && textureLocations.find(colTex) == textureLocations.end()) {
             colTex = nullptr;
         }
         if (colTex == nullptr && colProp.IsValid()) {
             colorVal = colProp.Get<FbxDouble3>();
         }
         FbxFileTexture *facTex = facProp.GetSrcObject<FbxFileTexture>();
-        if (facTex != nullptr && textureNames.find(facTex) == textureNames.end()) {
+        if (facTex != nullptr && textureLocations.find(facTex) == textureLocations.end()) {
             facTex = nullptr;
         }
         if (facTex == nullptr && facProp.IsValid()) {
@@ -240,7 +240,7 @@ class FbxMaterialsAccess
 {
 public:
 
-    FbxMaterialsAccess(const FbxMesh *pMesh, const std::map<const FbxTexture *, FbxString> &textureNames) :
+    FbxMaterialsAccess(const FbxMesh *pMesh, const std::map<const FbxTexture *, FbxString> &textureLocations) :
         mappingMode(FbxGeometryElement::eNone),
         mesh(nullptr),
         indices(nullptr)
@@ -272,7 +272,7 @@ public:
             if (summary == nullptr) {
                 summary = summaries[materialNum] = std::make_shared<FbxMaterialAccess>(
                     mesh->GetNode()->GetSrcObject<FbxSurfaceMaterial>(materialNum),
-                    textureNames);
+                    textureLocations);
             }
         }
     }
@@ -473,7 +473,7 @@ GetMaterialType(const RawModel &raw, const int textures[RAW_TEXTURE_USAGE_MAX],
     return skinned ? RAW_MATERIAL_TYPE_SKINNED_OPAQUE : RAW_MATERIAL_TYPE_OPAQUE;
 }
 
-static void ReadMesh(RawModel &raw, FbxScene *pScene, FbxNode *pNode, const std::map<const FbxTexture *, FbxString> &textureNames)
+static void ReadMesh(RawModel &raw, FbxScene *pScene, FbxNode *pNode, const std::map<const FbxTexture *, FbxString> &textureLocations)
 {
     FbxGeometryConverter meshConverter(pScene->GetFbxManager());
     meshConverter.Triangulate(pNode->GetNodeAttribute(), true);
@@ -490,7 +490,7 @@ static void ReadMesh(RawModel &raw, FbxScene *pScene, FbxNode *pNode, const std:
     const FbxLayerElementAccess<FbxVector2> uvLayer0(pMesh->GetElementUV(0), pMesh->GetElementUVCount());
     const FbxLayerElementAccess<FbxVector2> uvLayer1(pMesh->GetElementUV(1), pMesh->GetElementUVCount());
     const FbxSkinningAccess                 skinning(pMesh, pScene, pNode);
-    const FbxMaterialsAccess                materials(pMesh, textureNames);
+    const FbxMaterialsAccess                materials(pMesh, textureLocations);
 
     if (verboseOutput) {
         fmt::printf(
@@ -562,9 +562,9 @@ static void ReadMesh(RawModel &raw, FbxScene *pScene, FbxNode *pNode, const std:
 
             const auto maybeAddTexture = [&](FbxFileTexture *tex, RawTextureUsage usage) {
                 if (tex != nullptr) {
-                    // dig out the inferred filename from the textureNames map
+                    // dig out the inferred filename from the textureLocations map
-                    const char *inferredPath = textureNames.find(tex)->second;
+                    FbxString inferredPath = textureLocations.find(tex)->second;
-                    textures[usage] = raw.AddTexture(tex->GetName(), inferredPath, usage);
+                    textures[usage] = raw.AddTexture(tex->GetName(), tex->GetFileName(), inferredPath.Buffer(), usage);
                 }
             };
 
@@ -708,7 +708,8 @@ static void ReadCamera(RawModel &raw, FbxScene *pScene, FbxNode *pNode)
     }
 }
 
-static void ReadNodeAttributes(RawModel &raw, FbxScene *pScene, FbxNode *pNode, const std::map<const FbxTexture *, FbxString> &textureNames)
+static void ReadNodeAttributes(
+    RawModel &raw, FbxScene *pScene, FbxNode *pNode, const std::map<const FbxTexture *, FbxString> &textureLocations)
 {
     if (!pNode->GetVisibility()) {
         return;
@@ -723,7 +724,7 @@ static void ReadNodeAttributes(RawModel &raw, FbxScene *pScene, FbxNode *pNode,
             case FbxNodeAttribute::eNurbsSurface:
             case FbxNodeAttribute::eTrimNurbsSurface:
             case FbxNodeAttribute::ePatch: {
-                ReadMesh(raw, pScene, pNode, textureNames);
+                ReadMesh(raw, pScene, pNode, textureLocations);
                 break;
             }
             case FbxNodeAttribute::eCamera: {
@@ -752,7 +753,7 @@ static void ReadNodeAttributes(RawModel &raw, FbxScene *pScene, FbxNode *pNode,
     }
 
     for (int child = 0; child < pNode->GetChildCount(); child++) {
-        ReadNodeAttributes(raw, pScene, pNode->GetChild(child), textureNames);
+        ReadNodeAttributes(raw, pScene, pNode->GetChild(child), textureLocations);
     }
 }
 
@@ -944,7 +945,7 @@ static void ReadAnimations(RawModel &raw, FbxScene *pScene)
     }
 }
 
-static std::string GetInferredFileName(const char *fbxFileName, const char *directory, const std::vector<std::string> &directoryFileList)
+static std::string GetInferredFileName(const std::string &fbxFileName, const std::string &directory, const std::vector<std::string> &directoryFileList)
 {
     // Get the file name with file extension.
     const std::string fileName = Gltf::StringUtils::GetFileNameString(Gltf::StringUtils::GetCleanPathString(fbxFileName));
@@ -956,25 +957,19 @@ static std::string GetInferredFileName(const char *fbxFileName, const char *dire
         }
     }
 
-    // Some FBX textures end with "_c.dds" while the source texture is a ".tga".
-    const bool isDDS = fileName.rfind("_c.dds") != std::string::npos;
-
     // Get the file name without file extension.
-    const std::string fileBase = isDDS ? fileName.substr(0, fileName.length() - 6) : Gltf::StringUtils::GetFileBaseString(fileName);
+    const std::string fileBase = Gltf::StringUtils::GetFileBaseString(fileName);
 
     // Try to find a match without file extension.
     for (const auto &file : directoryFileList) {
-        const std::string listedFileBase = Gltf::StringUtils::GetFileBaseString(file.c_str());
-
         // If the two extension-less base names match.
-        if (Gltf::StringUtils::CompareNoCase(fileBase, listedFileBase) == 0) {
+        if (Gltf::StringUtils::CompareNoCase(fileBase, Gltf::StringUtils::GetFileBaseString(file)) == 0) {
             // Return the name with extension of the file in the directory.
             return std::string(directory) + file;
         }
     }
 
-    // Return the original file with extension
+    return "";
-    return fbxFileName;
 }
 
 /*
@@ -987,30 +982,34 @@ static std::string GetInferredFileName(const char *fbxFileName, const char *dire
     it to a list of existing texture files in the same directory as the FBX file.
 */
 static void
-FindFbxTextures(FbxScene *pScene, const char *fbxFileName, const char *extensions, std::map<const FbxTexture *, FbxString> &textureNames)
+FindFbxTextures(
+    FbxScene *pScene, const char *fbxFileName, const char *extensions, std::map<const FbxTexture *, FbxString> &textureLocations)
 {
     // Get the folder the FBX file is in.
-    const FbxString folder = Gltf::StringUtils::GetFolderString(fbxFileName).c_str();
+    const std::string folder = Gltf::StringUtils::GetFolderString(fbxFileName);
 
     // Check if there is a filename.fbm folder to which embedded textures were extracted.
-    const FbxString fbmFolderName = folder + Gltf::StringUtils::GetFileBaseString(fbxFileName).c_str() + ".fbm/";
+    const std::string fbmFolderName = folder + Gltf::StringUtils::GetFileBaseString(fbxFileName) + ".fbm/";
 
     // Search either in the folder with embedded textures or in the same folder as the FBX file.
-    const FbxString searchFolder = FileUtils::FolderExists(fbmFolderName) ? fbmFolderName : folder;
+    const std::string searchFolder = FileUtils::FolderExists(fbmFolderName) ? fbmFolderName : folder;
 
     // Get a list with all the texture files from either the folder with embedded textures or the same folder as the FBX file.
-    std::vector<std::string> fileList;
+    std::vector<std::string> fileList = FileUtils::ListFolderFiles(searchFolder.c_str(), extensions);
-    FileUtils::ListFolderFiles(fileList, searchFolder, extensions);
 
     // Try to match the FBX texture names with the actual files on disk.
     for (int i = 0; i < pScene->GetTextureCount(); i++) {
-        const FbxTexture     *pTexture     = pScene->GetTexture(i);
+        const FbxFileTexture *pFileTexture = FbxCast<FbxFileTexture>(pScene->GetTexture(i));
-        const FbxFileTexture *pFileTexture = FbxCast<FbxFileTexture>(pTexture);
         if (pFileTexture == nullptr) {
             continue;
         }
-        const FbxString name = GetInferredFileName(pFileTexture->GetFileName(), searchFolder, fileList).c_str();
+        const std::string inferredName = GetInferredFileName(pFileTexture->GetFileName(), searchFolder, fileList);
-        textureNames.emplace(pTexture, name);
+        if (inferredName.empty()) {
+            fmt::printf("Warning: could not find a local image file for texture: %s.\n"
+            "Original filename: %s\n", pFileTexture->GetName(), pFileTexture->GetFileName());
+        }
+        // always extend the mapping, even for files we didn't find
+        textureLocations.emplace(pFileTexture, inferredName.c_str());
     }
 }
 
@@ -1041,8 +1040,8 @@ bool LoadFBXFile(RawModel &raw, const char *fbxFileName, const char *textureExte
         return false;
     }
 
-    std::map<const FbxTexture *, FbxString> textureNames;
+    std::map<const FbxTexture *, FbxString> textureLocations;
-    FindFbxTextures(pScene, fbxFileName, textureExtensions, textureNames);
+    FindFbxTextures(pScene, fbxFileName, textureExtensions, textureLocations);
 
     // Use Y up for glTF
     FbxAxisSystem::MayaYUp.ConvertScene(pScene);
@@ -1054,7 +1053,7 @@ bool LoadFBXFile(RawModel &raw, const char *fbxFileName, const char *textureExte
     }
 
     ReadNodeHierarchy(raw, pScene, pScene->GetRootNode(), "", "");
-    ReadNodeAttributes(raw, pScene, pScene->GetRootNode(), textureNames);
+    ReadNodeAttributes(raw, pScene, pScene->GetRootNode(), textureLocations);
     ReadAnimations(raw, pScene);
 
     pScene->Destroy();

src/Raw2Gltf.cpp

@@ -14,6 +14,7 @@
 
 #include "FBX2glTF.h"
 #include "utils/String_Utils.h"
+#include "utils/Image_Utils.h"
 #include "RawModel.h"
 #include "Raw2Gltf.h"
 
@@ -362,25 +363,25 @@ ModelData *Raw2Gltf(
         for (int textureIndex = 0; textureIndex < raw.GetTextureCount(); textureIndex++) {
             const RawTexture  &texture         = raw.GetTexture(textureIndex);
             const std::string textureName      = Gltf::StringUtils::GetFileBaseString(texture.name);
-            const std::string texFilename = texture.fileName;
+            const std::string relativeFilename = Gltf::StringUtils::GetFileNameString(texture.fileLocation);
 
             ImageData *source = nullptr;
             if (options.outputBinary) {
-                auto bufferView = gltf->AddBufferViewForFile(buffer, texFilename);
+                auto bufferView = gltf->AddBufferViewForFile(buffer, texture.fileLocation);
                 if (bufferView) {
-                    source = new ImageData(textureName, *bufferView, "image/png");
+                    std::string suffix = Gltf::StringUtils::GetFileSuffixString(texture.fileLocation);
+                    source = new ImageData(relativeFilename, *bufferView, suffixToMimeType(suffix));
                 }
 
             } else {
-                // TODO: don't add .ktx here; try to work out a reasonable relative path.
+                source = new ImageData(relativeFilename, relativeFilename);
-                source = new ImageData(textureName, textureName + ".ktx");
             }
             if (!source) {
                 // fallback is tiny transparent gif
                 source = new ImageData(textureName, "data:image/gif;base64,R0lGODlhAQABAAD/ACwAAAAAAQABAAACADs=");
             }
 
-            TextureData &texDat = *gltf->textures.hold(
+            const TextureData &texDat = *gltf->textures.hold(
                 new TextureData(textureName, defaultSampler, *gltf->images.hold(source)));
             assert(texDat.ix == textureIndex);
         }

src/RawModel.cpp

@@ -84,9 +84,9 @@ int RawModel::AddTriangle(const int v0, const int v1, const int v2, const int ma
     return (int) triangles.size() - 1;
 }
 
-int RawModel::AddTexture(const char *name, const char *fileName, const RawTextureUsage usage)
+int RawModel::AddTexture(const std::string &name, const std::string &fileName, const std::string &fileLocation, RawTextureUsage usage)
 {
-    if (name[0] == '\0') {
+    if (name.empty()) {
         return -1;
     }
     for (size_t i = 0; i < textures.size(); i++) {
@@ -95,7 +95,7 @@ int RawModel::AddTexture(const char *name, const char *fileName, const RawTextur
         }
     }
 
-    const ImageProperties properties = GetImageProperties(fileName);
+    const ImageProperties properties = GetImageProperties(!fileLocation.empty() ? fileLocation.c_str() : fileName.c_str());
 
     RawTexture texture;
     texture.name         = name;
@@ -106,6 +106,7 @@ int RawModel::AddTexture(const char *name, const char *fileName, const RawTextur
     texture.occlusion    = (properties.occlusion == IMAGE_TRANSPARENT) ?
                            RAW_TEXTURE_OCCLUSION_TRANSPARENT : RAW_TEXTURE_OCCLUSION_OPAQUE;
     texture.fileName     = fileName;
+    texture.fileLocation = fileLocation;
     textures.emplace_back(texture);
     return (int) textures.size() - 1;
 }
@@ -313,7 +314,7 @@ void RawModel::Condense()
             for (int j = 0; j < RAW_TEXTURE_USAGE_MAX; j++) {
                 if (material.textures[j] >= 0) {
                     const RawTexture &texture = oldTextures[material.textures[j]];
-                    const int        textureIndex = AddTexture(texture.name.c_str(), texture.fileName.c_str(), texture.usage);
+                    const int textureIndex = AddTexture(texture.name, texture.fileName, texture.fileLocation, texture.usage);
                     textures[textureIndex] = texture;
                     material.textures[j] = textureIndex;
                 }

src/RawModel.h

@@ -122,13 +122,14 @@ enum RawTextureOcclusion
 
 struct RawTexture
 {
-    std::string         name;
+    std::string         name;           // logical name in FBX file
     int                 width;
     int                 height;
     int                 mipLevels;
     RawTextureUsage     usage;
     RawTextureOcclusion occlusion;
-    std::string         fileName;
+    std::string         fileName;       // original filename in FBX file
+    std::string         fileLocation;   // inferred path in local filesystem, or ""
 };
 
 enum RawMaterialType
@@ -233,7 +234,7 @@ public:
     void AddVertexAttribute(const RawVertexAttribute attrib);
     int AddVertex(const RawVertex &vertex);
     int AddTriangle(const int v0, const int v1, const int v2, const int materialIndex, const int surfaceIndex);
-    int AddTexture(const char *name, const char *fileName, const RawTextureUsage usage);
+    int AddTexture(const std::string &name, const std::string &fileName, const std::string &fileLocation, RawTextureUsage usage);
     int AddMaterial(const RawMaterial &material);
     int AddMaterial(
         const char *name, const char *shadingModel, RawMaterialType materialType,

src/glTF/ImageData.cpp

@@ -31,8 +31,9 @@ ImageData::ImageData(std::string name, const BufferViewData &bufferView, std::st
 
 json ImageData::serialize() const
 {
-    if (mimeType.empty()) {
+    if (bufferView < 0) {
         return {
+            { "name", name },
             { "uri", uri }
         };
     }

src/main.cpp

@@ -182,7 +182,7 @@ Copyright (c) 2016-2017 Oculus VR, LLC.
     if (verboseOutput) {
         fmt::printf("Loading FBX File: %s\n", inputPath);
     }
-    if (!LoadFBXFile(raw, inputPath.c_str(), "tga;bmp;png;jpg")) {
+    if (!LoadFBXFile(raw, inputPath.c_str(), "png;jpg;jpeg")) {
         fmt::fprintf(stderr, "ERROR:: Failed to parse FBX: %s\n", inputPath);
         return 1;
     }

src/utils/File_Utils.cpp

@@ -54,17 +54,17 @@ namespace FileUtils {
         return std::string(cwd);
     }
 
-    bool FolderExists(const char *folderPath)
+    bool FolderExists(const std::string &folderPath)
     {
 #if defined( __unix__ ) || defined( __APPLE__ )
-        DIR *dir = opendir(folderPath);
+        DIR *dir = opendir(folderPath.c_str());
         if (dir) {
             closedir(dir);
             return true;
         }
         return false;
 #else
-        const DWORD ftyp = GetFileAttributesA( folderPath );
+        const DWORD ftyp = GetFileAttributesA( folderPath.c_str() );
         if ( ftyp == INVALID_FILE_ATTRIBUTES )
         {
             return false;  // bad path
@@ -97,13 +97,12 @@ namespace FileUtils {
         return false;
     }
 
-    void ListFolderFiles(std::vector<std::string> &fileList, const char *folder, const char *matchExtensions)
+    std::vector<std::string> ListFolderFiles(const char *folder, const char *matchExtensions)
     {
+        std::vector<std::string> fileList;
 #if defined( __unix__ ) || defined( __APPLE__ )
         DIR *dir = opendir(folder);
-        if (dir == nullptr) {
+        if (dir != nullptr) {
-            return;
-        }
             for (;;) {
                 struct dirent *dp = readdir(dir);
                 if (dp == nullptr) {
@@ -125,6 +124,7 @@ namespace FileUtils {
             }
 
             closedir(dir);
+        }
 #else
         std::string pathStr = folder;
         pathStr += "*";
@@ -148,6 +148,7 @@ namespace FileUtils {
             FindClose( hFind );
         }
 #endif
+        return fileList;
     }
 
     bool CreatePath(const char *path)

src/utils/File_Utils.h

@@ -13,10 +13,10 @@
 namespace FileUtils {
     std::string GetCurrentFolder();
 
-    bool FolderExists(const char *folderPath);
+    bool FolderExists(const std::string &folderPath);
 
     bool MatchExtension(const char *fileExtension, const char *matchExtensions);
-    void ListFolderFiles(std::vector<std::string> &fileList, const char *folder, const char *matchExtensions);
+    std::vector<std::string> ListFolderFiles(const char *folder, const char *matchExtensions);
 
     bool CreatePath(const char *path);
 }

src/utils/Image_Utils.h

@@ -26,4 +26,20 @@ struct ImageProperties
 
 ImageProperties GetImageProperties(char const *filePath);
 
+/**
+ * Very simple method for mapping filename suffix to mime type. The glTF 2.0 spec only accepts values
+ * "image/jpeg" and "image/png" so we don't need to get too fancy.
+ */
+inline std::string suffixToMimeType(std::string suffix) {
+    std::transform(suffix.begin(), suffix.end(), suffix.begin(), ::tolower);
+
+    if (suffix == "jpg" || suffix == "jpeg") {
+        return "image/jpeg";
+    }
+    if (suffix == "png") {
+        return "image/png";
+    }
+    return "image/unknown";
+}
+
 #endif // !__IMAGE_UTILS_H__

src/utils/String_Utils.h

@@ -73,6 +73,16 @@ namespace Gltf // TODO replace
             return fileName.substr(0, fileName.rfind('.')).c_str();
         }
 
+        inline const std::string GetFileSuffixString(const std::string &path)
+        {
+            const std::string fileName = GetFileNameString(path);
+            unsigned long pos          = fileName.rfind('.');
+            if (pos == std::string::npos) {
+                return "";
+            }
+            return fileName.substr(++pos);
+        }
+
         inline int CompareNoCase(const std::string &s1, const std::string &s2)
         {
             return strncasecmp(s1.c_str(), s2.c_str(), MAX_PATH_LENGTH);